Filemaker Server 5.5 service terminating

Hi,

We have a system which consists of 75 hosted databases. About four of these databases are around the 1gb mark and the rest a no bigger than 200mb.

We migrated our system from a mac server to Windows NT in around 2000 and this solved our stability problems. Then in early 2001 we migrated to Windows 2000 and have been running fine until about a month ago.

We upgraded our server earlier this year to an Intel Xeon based system, processor running at 2.8ghz and we have run fine on this system for about 5 months.

Currently when ever any major tasks are being performed on the system (find's, updating of information) the service will quit. The message in event viewer says "filemaker server service unexpectedly terminated error 22")

I upgraded the network card drivers in the server as this was a recommendation by HP due to a problem with the earlier dirvers. The machine has always had Service Pack 4 installed.

The only change which has occured is we now have 60 hosts, the server is setup to allow 70 hosts. All the client machines are running Filemaker 5.0v3.

Are there any know issues running Filemaker Server 5.5v1 on a Windows 2000 Server with an Intel Xeon processor?

Should we update are client machiens to Filemaker 6.0v4?

How can I see what has caused the service to quite?

What is errro 22?

Many thanks for your time.